Jet engine having a plurality of turbocompressors operable in parallel or in series



Jan. 1, 1952 R J ourr 2,580,591

JET ENGINE HAVING A PLURALITY OF TURBOCOMPRESSORS OPERABLE IN PARALLELOR IN SERIES Filed Oct. 26, 1945 4 Sheets-Sheet l I [/VT ROBERT Eg AN 50IT A TTORNE Y5 Jan. 1, 1952 ourr 2,580,591

R. J. JET ENGINE HAVING A PLURALITY OF TURBOCOMPRESSORS OPERABLE INPARALLEL OR IN SERIES Filed Oct. 26, 1945 4 Sheets-Sheet 2 c/ulih- 64/50 k I J 6 I/VVENTOR ROBERT TEAN POUIT BY M W A TTOR NEYS Jan. 1, 1952oun- 2,580,591

JET ENGINE HAVING A PLURALITY OF TURBOCOMPRESSORS OPERABLE IN PARALLELOR IN SERIES Filed 001'. 26, 1945 4 Sheets-Sheet 5 aotoyenerataIA/I/EIVTOIY ROBERT JEAN POUIT 8y MHE W ATTOR/VITYJ R. J. POUIT Jan. 1,1952 JET ENGINE HAVING A PLURALITYOF TURBOCOMPRESSO OPERABLE IN PARALLELOR IN SERIES Filed Oct. 26, 1945 4 Sheets-Sheet 4 //VV/VTOR ROBERT- TEANRoun- M M ATTORNEYS Patented Jan. 1, 1952 JET ENGINE HAVING A P LURALITIOF TURBOCOMPRESSORS OPERABLE IN PARALLEL OR IN SERIES Robert Jean Pouit,Lyon, France, assignor to Societe Industrielle Gener'ale de MccaniqueAppliquee (S. I. G. M. A.), Venlsseux (Rhone), France, a society ofFrance Application October 26, 1945, Serial No. 624,736 In FranceDecember 30, 1944 16 Claims.

The present invention relates to jet propulsion plants and moreespecially, although not exclusively, jet propulsion plants foraircrafts.

Such a plant includes at least one multiple stage air compressor deviceand at least one multiple stage motor device, the latter, which servesto drive the former, being fed with gases supplied by said compressorand in which a certain amount of fuel is burned.

In aircraft propelling plants making use of the reaction obtained by theejection of gases under pressure, the system for the production of thesegases is generally designed in such manner as to obtain the powernecessary for the propulsion with a high efliciency when flying at highaltitudes. On the other hand, it is often diflicult to reach thesealtitudes and in particular to take oil by means of the jet propulsionplant alone, due to the insuflicient driving power at low altitudes ofjet plants as known at the present time, which is due to the lowefliciency of the compressor and motor devices at altitudes considerablylower than the altitudeof utilization for which the plant has beenstudied.

Furthermore, it should be noted that the propelling efliciency of jetplants is very low when the translatory and ejection speeds are verydifferent, which is the case for aircraft plants during the startingperiod. The jet plant must therefore be able to supply, during thisperiod, an important amount of energy in the driving gases, whichsurplus should be kept up to an altitude as high as possible so as toreach in a time as short as possible the altitude of normal utilization,where the efllciency is maximum.

The chief object of my invention is to provide a. jet propulsion plantcapable of working satisfactorily under very different loads anddifierent conditions, especially in the case of apropelling plantfor anaircraft, which must, on the one hand, have a good efliciency at" highaltitudes of flight, and, on the other hand, be capable of supplying, atthe take off and during the subsequent climb, the power necessary forthese conditions of flight.

Other objects of my invention will result from the following detaileddescription of some specific embodiments thereof with reference to theaccompanying drawings, given merely by way of example, and in which:

Fig. 1 diagrammatically shows a first embodiment of a power plantaccording to the invention;

(Cl. (ill-35.6)

z Fig. 2 is a similar view of a second embed ment;

Fig. 3 is a diagrammatical view of an automatic control device for useaccording to the invention;

Fig. 4 shows a modification of either of the embodiments of Figs. 1 and2;

Fig. 5 shows a fuel combustion device for use in a plant according tothe invention;

Figs. 6 to 8 inclusive are diagrammatical views, partly in section andpartly in elevation, of three other embodiments of a propelling plantaccording to the invention;

Fig. 7a is a rear end view corresponding to Fi 7; r

Fig. 7b is a view, partly in section, of an element of the structure ofFig. 7;

Fig. 9 is a view on an enlarged scale of a part of the plant shown byFig. 8.

All these drawings relate to propulsion plants for aircrafts.

In the embodiment of Fig. 1, the means for producing the propellinggases are constituted exclusively by rotary machines.

The air compressor device is divided into two groups, to wit group I(low pressure group) and group 2 (high pressure group). Each of thesegroups can itself include several stages.

The inflow of air intothe low pressure compressor group I takes placethrough air intake 3 and the air compressed in this group is dischargedthrough conduit 4.

Concerning the high pressure compressor group 2, the air intake is at 5and the outlet at 6.

The motor device of the plant includes a high pressure group constitutedby a multiple stage.

gas turbine I and a low pressure group constituted by a multiple stagegas turbine 8. Of course, these two gas turbines 1 and 8 can be combinedinto a single turbine a plurality of stages of which constitutes thehigh pressure group while a plurality of other stages constitutes thelow pressure group.

The shaft of the high pressure turbine I is coupled with that of thehigh pressure compressor 2 so as to drive it, while the shaft of the lowpressure turbine 8 is coupled with the shaft of the low pressurecompressor I.

The two high pressure groups I and 2 constitute a unit and the two lowpressure groups I and 8 comtitute another unit. In each unit, theturbine is arranged and dimensioned in such manner as to supply thecorresponding compressor with the energy strictly suflicient forensuring therein the necessary compression.

According to the invention, means are provided for permitting at willeither the operation in series of the two units thus constituted, ortheir operation in parallel.

For this purpose, the discharge conduit 4 of the low pressure compressorl is connected on the one hand, through a conduit 9 with the suction 5of the high pressure compressor 2 and, on the other hand, through abranch conduit ID, with the intake of the low pressure turbine 8.

Furthermore, a second air intake l l, connected with the inlet 5 of thehigh pressure compressor 2, is provided for feeding this compressor withair from the surrounding atmosphere, and the delivery 6 of saidcompressor is connected through a conduit l2 with the inlet of the highpressure turbine l the exhaust of which can be connected, either througha conduit 63 with the input of the low pressure turbine 8, or through aconduit 14 with an expansion nozzle 55 through which the gases aredischarged into the atmosphere in such manner as to ensure thepropulsion of the aircraft. Furthermore, the exhaust of the low pressureturbine 8 is connected, through conduits 8a, with another expansionnozzle ii.

In each of the two feed conduits i and I2, leading respectively to thelow and high pressure turbines 8 and 1, there is interposed a combustionchamber H, 38, respectively, for burning a certain amount of fuel in theair under pressure intended to be fed to the corresponding turbine,before said air enters said turbine.

Finally, control means, for instance two-way cocks I9, 20 and 2|, areprovided in the various conduits for permitting either the operation inseries or that in parallel of the two units that constitute thepropulsion plant.

The position of cocks I9, 20- and 25 shown by Fig. 1 corresponds to theworking in parallel, which is to be used on the ground or at lowaltitude. When the system is working in parallel, the air sucked in fromthe surrounding atmosphere enters simultaneously through intakes 3 andIl into compressors l and 2, respectively. The air supplied bycompressor I is fed through conduit 10 into combustion chamber H, fromwhich it passes to turbine B, in which it expands, while driving saidturbine, down to a pressure slightly above that of the surroundingatmosphere. When issuing from turbine 8, the air stream is fed throughconduit 8a to expansion nozzle l6, from which it escapes into theatmosphere, producing by reaction a'certain propelling force.

Concerning now the air compressed by compressor 2, it is heated incombustion chamber l8 before entering turbine I. In driving thisturbine, said air expands to a pressure slightly above the pressure ofthe surrounding atmosphere. It is fed through conduit 14 to nozzle fromwh ch it escapes, also tranmitting a jet impulsion to the aircraft. a

When the system is working in series, cock I!) is given a position suchthat it places the output 4 01. compressor l in communication with theinput 5 of compressor 2 and simultaneous y cuts oil the communicationbetween, on the one hand, branch conduit [0 and, on the other hand,combustion chamber [1 and also the input of turbine 8, this combustionchamber being thus brought out of action.

Cock 20, in the position thereof corresp ndin to the working in seriesof the system. cuts off the communication between air intake l l and theinlet 5 of the high pressure compressor 2. Fi-'- nally, cock 2! on theone hand cuts oil, for the position thereof corresponding to thisworking, the communication between the exhaust of turbine I andexpansion nozzle l5, which is thus brought out of action, and on theother hand opens conduit I3, which connects the exhaust of turbine lwith the intake of turbine 8.

Thus, the air admitted through air intake 3 is compressed a first timein compressor I and a second time in compressor 2, connected in serieswith the first compressor. This air has been heated in combustionchamber l8 so as to drive, when expanding, first turbine I and thenturbine 8. Finally, the air issuing from turbine 8 through conduits 8apasses to nozzle l6 so as to be ejected into the atmosphere in suchmanner as to ensure the propulsion of the aircraft.

As above stated, the working in parallel of the two units I8 and 2-l isused for the take of]! and for quick climbing to the normal altitude ofutilization, that is to say when the plant is to supply a very highpower. In this case, each of the two units in question, sucking in airdirectly from the atmosphere, where the pressure is relatively high,compresses a great weight of air to pressures that remain within theusual limits, this air serving to the combustion, in two combustionchambers I1 and I8, of a great amount of fuel. It should be noted thatthe low pressure unit l-8, being of dimensions much greater than thoseof the high pressure unit 2-'|, is capable, at low altitude, ofsupplying a power that is very important and considerably higher thanthat supplied by the high pressure unit The operation in series is used,in particular, for high altitude flying, which constitutes the normalconditions of working of the plant. For such operation, only the lowpressure compressor l receives air from the surrounding atmosphere andonly combustion chamber I8 is in action for burning fuel in thecompressed air.

In order to obtain the best possible working of the plant, not only forthe operation in series but also for that in parallel, it isadvantageous to design the plant in such manner that, for high altitudeflying, i. e. for instance at a height of 15,000 metres, where theatmospheric pressure is about 0.12 kg. per sq. cm., the dischargepressure oi the low pressure compressor l is about 1 kg. per sq. cm.,that is to say the atmospheric pressure on the ground level.

On the other hand, the plant is constructed in such manner that theexhaust pressure at the output of high pressure turbine I is a littlehigher than the atmospheric pressure in the vicinity of the groundlevel. This exhaust pressure, which is for instance equal to 1.5 kg. persq. cm., ensures, on the one hand, for the working in parallel of thesystem, a suitable speed of ejection of the driving gases issuing fromnozzle l5, and, on the other hand, for the working in series, asuificient expansion in the low pressure turbine 8, the exhaust pressureof which, in such conditions of operations, is, at a height of about15,000 metres, for instance 0.3 kg. per sq. cm., this value beingsufiiciently above the pressure of the surrounding atmosphere, which is0.12 kg. per sq. cm., for ensuring a suitable speed of the gases issuingthrough nozzle l8.

It results from the preceding indications that the conditions underwhich the high pressure unit 21 is called to work are alwayssubstantially the same, both for the operation in series and theoperation in parallel of the plant.

Concerning more especially the low pressure unit l8, the feed of fuelinjected into combustion chamber IT for the working in parallel isadjusted in such manner as preferably to obtain always the same speed ofrevolution of this unit for the working in parallel as for the workingin series, thus ensuring always the same ratio of compression in the lowpressure compressor l.

Furthermore, and advantageously, the system is arranged in such mannerthat, the speeds of revolution being substantially constant. the speedsof introduction into the wheels of turbine 8 are also alwayssubstantially constant.

For this purpose, the driving gases coming,

during the working in parallel, from the low pressure compressor I, andwhich have been heated in combustion chamber H, are introduced:

(a) Either into the first stage of the low pressure turbine 8 and thisin the case of the volume of these gases being equal to that 01' thegases issuing during the working in series, from the high pressureturbine 1;

(b) Or into a stage of the low pressure turbine 8 downstream of thefirst stage (see for instance Fig. 2), this in the case of the volume ofthe gases coming from compressor I and combustion chamber I! beinggreater than the volume of the gases coming, during the working inseries, from the high pressure turbine I, this excess being due forinstance .to the considerable increase of the temperature of the gasesin said combustion chamber ll.

Finally, if, in the working in parallel, the volume of the gases comingfrom compressor I and combustion chamber II were smaller than the volumeof the gases introduced into turbine 8' during the working in series, Imay, either provide means for withdrawing, upstream of turbine 8. thegases that are being fed thereto during the working in parallel, forinstance a throttle 22 provided in conduit I0, so as thus to obtainequality of the volumes of gases fed to said turbine during the workingin parallel and the working in series respectively; or cause the gasesfrom said turbine 8 to escape therefrom, during the working in parallel,at a point located upstream of the last wheel or wheels thereof, forinstance through a conduit 23 which short-circuits the last wheel orwheels of turbine 8.

According to another embodiment of the invention which is particularlyadvantageous, I provide, instead of the combustion chamber I 8 of Fig.1, an engine of the piston type which is fed with air compressed by thehigh pressure compressor and the exhaust gases of which are introducedat a suitable pressure into the high pressure turbine I. Preferably,this engine is of the two-stroke type, whereby the exhaust gases fromthis engine, which are constituted by the combustion gases and theexcess or the scavenging air and feed air have a pressure substantiallyequal to the feed pressure of said engine.

Fig. 2 shows an example of this last mentioned construction.

In Fig. 2, I have designated all the parts that are identical oranalogous to certain parts of Fig. 1 by the same reference numerals ason this figure. Furthermore, in Fig. 2, lfla designates the two-strokeengine which replaces the combustion chamber l8 of Fig. 1, and Ho andl2b are the feed conduit and the exhaust conduit or this engine.

The supplement of mechanical energy that is supplied by engine 18aserves, in the embodiment illustrated by Fig. 2, to drive a blower 24which communicates, through conduits 25, with expan-- blower 24 incommunication with one or/and the other of said compressors, thesuper-charging air being caused to pass through branch conduitsrespectively designated by 30 and 29.

'The plant shown by Fig. 2 is further fitted with two communicationconduits I 3, I31 between the outlet of high pressure turbine 'l and theinlet of low pressure turbine 8.

In conduit I3 is interposed two-way cock l9a which, in one of itspositions, allows air coming from the low pressure compressor I to flowthrough conduit l0 into combustion chamber I1, from which this airenters into one stage of tur-' bine 8 located, for instance, downstreamof the first stage of this turbine, whereas said cock I90, in its otherposition, closes conduit l0 and opens conduit l3.

In conduit I31 is interposed a two-way cock 2! which, in one of itspositions connects expansion nozzle l5 with the exhaust of turbine l andcloses conduit 131, whereas, in theother position, it closes saidcommunication and opens said conduit I 31.

Finally, in some cases, it may be advantageous to interpose in theconduit I2b which connects the exhaust of engine I8a with the inlet ofhigh pressure turbine i, a supplementaiy combustion chamber 3| throughwhich it is possible, under certain working conditions, to increase thepower of the plant beyond its normal power in order to meet certaindifiiculties.

All that has been said in the description with reference to Fig. 1concerning the keeping of the speed of revolution of unit l-8 at aconstant value and the means for keeping ata substantially constantvalue the speed of introduction of the gases into the low pressureturbine 8 also applies to the plant illustrated by Fig. 2. I

Concerning the operation of this plant, it is, as

'a rule, the same as that of the plant of Fig. 1.

During the take cfi and when flying at low and intermediate altitudes,for instance up to a height of 9,000 m. the two main units of the plant,to wit 2--l8al and i--ll8 work in parallel, that is to say the gasesexpanded in the high pressure turbine 1 are fed to expansion nozzle l5and those expanded in the low pressure turbine 8 are fed to expansionnozzle l6. Cocks l9, [Saand 2 are, during the working in parallel, inthe positions shown by Fig. 2. Above the height above mentioned, theworking in parallel is replaced by the working in series, for whichcombustion chamber I1 is taken out of action. In this case, cocks [9,I911, 23 and 2| are brought into a position such that the air compressedby the low pressure compressor I is fed to the high pressure compressor2, in which it is further compressed. This air is then introduced intoengine [8a, for which it constitutes the feed and scavenging air. Thegases escaping from this engine are introduced into turbine I where theyundergo a first expansion; then they pass through conduits I3,

I31 into the low pressure turbine 8 where they undergo a secondexpansion, down to a pressure higher. than the atmospheric pressure by adifference such that a speed of ejection of the gases" from nozzle I6 isobtained which ensures a good efficiency of the propulsion.

It should be noted that, for the working in series, for which cook is inthe position shown by Fig. 2, cock 21 must be in the positioncorresponding to the closing of branch conduit 29.

For the good working of the plant of Fig. 2, it is absolutely necessaryto have the feed pressure of engine 18a kept at a substantially constantvalue for all altitudes of flight. For this reason, I have provided, inaddition to the possibility of passing from the working in parallel ofthe two main units to the workin in series and vice-versa, on the onehand means (cock 2! and air intake ll) permitting, when working inparallel, either of supercharging the high pressure compressor 2 bymeans of the air compressed by blower 24, or of ,feeding said compressordirectly from the atmosphere, and, on the other hand, means (cock 28 andair intake 3) permitting, as well when operating both units in parallelas when operating them in series, either of supercharging compressor lby means of the air already compressed by blower 24, or of feeding saidcompressor l directly from the atmosphere.

Concerning the control of the cooks which serve to pass to the workingin parallel from the working in series and vice-versa and to bring intoand out of action combustion chamber ll which serves merely when theunits are working in parallel, this control may of course be performedmanually. However, according to a particularly advantageous feature ofthe invention, this control is automatically performed, for instance inresponse to variations of the altitude at which the aircraft providedwith the power plant is flying.

A control device of this type is shown by Fig. 3 by way of example.

Cock I9 is directly actuated by a control lever 32. Cook 20 is connectedwith this lever 32 through a lever 20' and a link 20". Cock 2| isconnected to lever 32 through a lever 2| and a link 2|". Said controllever 32 is operated by one or several barometric boxes 33. Thesebarometric means may act either directly, as shown by the drawing, or,preferably, through the intermediate of electric, pneumatic, magnetic orhydraulic relays which, since they constitute devices known inthemselves, need not be described here. 1

In the case, shown by the drawing, of a direct control, the manometricsystem 33 is connected with control element 32 through rods such as 34,35, 36 and 31 and bell crank levers such as 38 and 39 at least one ofwhich, for instance lever 39, is subjected to the action of a spring 40which tends to keep element 32 in one or the other of the two positionsfor which cocks l9, etc. ensure the working of the units of the planteither in series or in parallel. 39 and manometric means 33, there isinterposed an'elastic connection constituted, for instance, by a piston4| and a cylinder 42 cooperating together through the intermediate oftwo springs 43 and 44 having mutually opposing actions.

In order to bring combustion chamber l'l into or out of action, Icombine with the parts above mentioned means for igniting the fuelinjected into said chamber when passing from the work- Between bellcrank lever ing in series to the working in parallel. For this purpose,chamber i1 is provided with a platinum wire 45 electrically heatedthrough an electric circuit which is closed in the position shown byFig. 3; which corresponds to the working in parallel, this circuit beingclosed through a contact element 46 in contact with lever 39.

The same electric circuit may advantageously be used for feeding currentto the electric motor of the motor pump unit 41 which feeds fuel to theburners of chamber II.

This device works as follows:

On the ground, this device is in the position shown by Fig. 3, whichcorresponds to the working in parallel. After the take ofi and as theair craft is climbing, manometric means 33 expand. This movement istransmitted through connection 34, 38, 35 to cylinder 42, which thuscompresses spring 43. Piston 4| is first kept in fixed position, due tothe preponderating action of spring 40 on element 39, whereby theposition of the cooks corresponding to the working in parallel remainsunchanged.

However, when a certain height has been reached, for instance at aheight of 9,000 metres, the action of spring 43 causes lever 30 to swinginto its other position, for which the cocks are brought into respectivepositions corresponding to the working in series and the circuit to 45is opened, which stops the working of the fuel pump 41. The whole systemis kept in this new position owing to the action of spring 40 which nowoccupies a position symmetrical with respect to its initial position andfor which the action of spring 44, which is more and more flattened asthe altitude increases, is overcome by that of spring 40.

When the aircraft moves toward the ground, the system worksautomatically in the opposite way, so as to be brought back into itsinitial position when the height drops below 9,000 metres.

In some cases,"it may be advantageous to provide means for limiting,under certain conditions, the amount of fuel injected into combustionchamber I'I so as thus to prevent the temperature of the gases used forpropulsion from exceeding a given admissible value.

This limiting device is also shown by Fig. 3 and is essentiallyconstituted by a deformable box 50 cooperating with a rod 49 whichconstitutes the quantitative adjustment means for fuel pump 41.

This box 50 is connected with a fluid thermometer 5| subjected, througha connection 52, to the temperature of the gases as they leavecombustion chamber [1. 50, which expands more and more as thetemperature of the gases rises and which gradually contracts when thistemperature drops, constitutes an abutment limiting the movement of rod49 in the direction corresponding to increases of the amount of fuelinjected into the combustion chamber. Preferably, this rod is urged by aspring 51 in such manner that an adjustable finger 56 tends to bearagainst the bottom of box 50 which acts ,as an abutment. A control 58,58a permits of reducing the amount'of fuel that is injected to a valuebelow that correspond ing to the maximum fixed by abutment 50.

According to another feature of the invention, means are provided forburning a certain supplementary amount of fuel between the twosuccessive stages of the motor device constituted by turbines l and 8,preferably by making use, for the working in series, of combustion cham-This deformable box ber I I which, normally, is employed only for theworking in parallel.

According to the embodiment illustrated by Fig. 4, this combustion of asupplementary amount of fuel takes place, for the working in series,between the high and low pressure turbines 7 and 8, and it is intendedto bring, for a certain time, the power of the plant beyond its normalvalue, for instance in order to increase the climbing speed of theaircraft so that it can get quicker to its normal flying height.

As shown by Fig. 4, a two-waycock 60 is interposed in conduit l3 andalso in conduit in and a point of conduit i3 located between cocks l9aand 80 is connected through a branch pipe 59 with a point of conduit 10also located between cocks Ho and 80. Y 4

When cocks Na and 80 are in the position shown by Fig. 4, the gasesflowing out from ture bine I pass, before entering turbine 8, throughcombustion chamber l1 in which they are heated by the combustion of acertain amount of fuel in said chamber. If it is preferred to have theworking in series without this supplementary heating, cock in is turnedin such manner as to cut off branch conduit 59 and to restore directcommunication between turbines I and 8.

Still another feature of the invention relates to the combustion in acombustion chamber such as H and I8 and its object is to obtain aspontaneous combustion, that is to say a combustion which requiresneither the use of fuel igniting means nor long flames, which permits ofmaking the combustion chamber of reduced size and weight.

According to this feature, a portion of the air supplied for instance bycompressor I for being fed, when working in parallel, to combustionchamber I1 is introduced into an auxiliary combustion chamber where arelatively considerable amount of fuel is burned so as to obtain atemperature such that this portion of the air, after it is mixed withthe remainder of the air fed by compressor I, gives a mixturesuillciently hot for ensuring the spontaneous combustion of the fuelinjected into the main combustion chamber.

An embodiment of the feature in question is 7 shown by Fig. 5, accordingto which the low pressure compressor i and the low pressu e turbine 8are disposed immediately one behind the other. The discharge of the lowpressure compressor is shown at 6i. From this discharge start, on theone hand conduit 9 which connects the low pressure compressor with thehigh pressure compressorand, on the other hand, a conduit Iliaconnecting Bl, chamber H, with the low pressure turbine 8. A valve 62pivoted about an axis 83 closes, in its horizontal position shown by thedrawing. conduit 9 and places Bl in communication with conduit Ilia; inits vertical position, shown in dotted lines, this valve closes conduitIlia and opens conduit 9.

n the common axis of turbine 8 and compressor l is mounted a fan 84which. can be uncoupled for the working in series and which sucks in airfrom conduit ifla through tube 85. The air thus sucked in is sent by fan64 through a tube 68 into an auxiliary combustion chamber 81 providedwith fuel injection means 8. Chamber 8'! is mounted on conduit Ilia withthe inside of which it communicates through apertures 69. Fig. showsthat the place where tube 05 sucks in air from conduit Ila is located onthrough combustion the downstream side of apertures 69 through which theair heated in auxiliary combustion chamber 81 is returned into the mainair stream.

Finally, combustion chamber I1, which is but 5 an extension of conduit"la, is provided with a plurality of fuel injectors 10.

The auxiliary combustion chamber arrangement of Fig. 5 works as follows:

During the working in parallel, for which valve 62 is in the horizontalposition shown by Fig. 5, the compressed air that leaves compressor lwith a temperature of, for instance, 320, enters conduit Illa and isimmediately mixed with the very hot air that is flowing out fromapertures 69 and which is, for instance, at a temperature of 1500" C.The temperature of the mixture thus formed is sufliciently high (forinstance 470) for ensuring spontaneous and quick combustion of the fuelwhich is injected through injectors 10 into the stream of air flowingthrough combustion chamber ii. The combustion of this last mentionedfuel raises the temperature at the outlet of the main-combustion chamberto,-for instance, 680 C. p

A portion of the mixture that is formed, immediately upon the enteringof air into conduit Ilia, by the adjunction of very hot air issuing fromauxiliary combustion chamber 61 is constantly sucked by fan 64 andreturned to the auxiliary combustion chamber. As this portion is alreadyat the initial temperature of the mixture, that is tosay about 470,spontaneous combustion is also ensured in the auxiliary combustionchamber. Besides, even if the suction by fan 64 took place at a pointupstream of apertures 69, there would be no difliculty in ensuring asteady combustion in the auxiliary combustion chamber, by making, forinstance said chamber in the form of a hot bulb the wall of which, onceheated to a sufficient temperature, would remain hot owing to thecombustion that takes place therein.

The provision of an auxiliary combustion chamber such as 61 makes itpossible to obtain an extremely quick and complete combustion withoutrequiring igniting means, whereby the size of the main combustionchamber I! can be considerably reduced.

The plants according to the invention that-are shown by Figs. 6 to 9inclusive are arranged in such manner as to ensure, for the working inparallel, an interconnection between the respective gas circuits thatfeed the turbine groups, this interconnection being preferably obtainedthrough a common manifold chamber from which all these groups are fedwith gas.

This intercommunication permits of compensating for the diiference thatmay exist, for the working in parallel, between the output of one of thecompressor groups and the requirements of the corresponding gas turbinegroup, by making use of the surplus output supplied by the othercompressor group with respect to the requirements of the turbine groupthat corresponds 55 to this last mentioned compressor group.

The gases admitted into the manifold chamber may be constituted eithersolely by air under pressure or, at least partly, by a mixture of airand combustion gas and this especially when 7 at least a portion of thedriving gases is supplied by an auto-generator of the piston typeconstituted by a motor element and a compressor element, the secondelement being driven by the first and supplying it with scavenging andcombustion air, the exhaust gases from the motor element constitutingthe driving gases to be supplied by the auto-generator.

The plant shown by Fig. 6 includes a compressor device divided into alow pressure group MI and a high pressure group, I02, each of thesegroups being constituted by a rotary blower.

The low pressure compressor group IOI receives air from the atmosphereat I03 and discharges compressed air at I04.

The high pressure compressor group I02 receives air at I05 anddischarges it at I06. The discharge end I04 of the low pressurecompressor group I M is connected with the inlet I05 of the highpressure compressor group I02 through, a conduit I01. This inlet I05 ofthe high pressure compressor I02 can further be connected with an airintake I08 for the direct feed of air from the atmosphere to this highpressure compressor. A valve I closes, in one of its positions (thatshown in solid lines on the drawing), this last mentioned air intakethus connecting the delivery end I04 of the low pressure compressor withthe inlet I of the high pressure compressor, while this valve I09, inits other position (shown in dotted lines) cuts off the communicationbetween delivery end 4 and inlet I05 and connects this inlet with airintake I08.

Compressors IN and I02 are driven by a low pressure gas turbine group H0and a, high pressure gas turbine group III, respectively.

"The high pressure turbine III has its inlet connected through conduitIIIa with a manifold chamber II2 which communicates, through conduitII3, with the delivery end I06 of the high pressure compressor I02.

The exhaust of turbine II I is connected, on the one hand, through aconduit H4, with a propelling nozzle II5 and, on the other hand, througha conduit H6, with the inlet of the low pressure turbine IIO. A valveIII closes one of these communications and opens the other, for oneposition of said valve, and vice-versa for the other position of saidvalve.

The inlet of the low pressure turbine H0 is further connected tomanifold I I2 through a conduit 0, a valve H9 being provided opening orclosing at will this communication while further closing or opening,respectively, the communication with the exhaust of the high pressureturbine III.

The exhaust of the low pressure turbine H0 is connected through conduitI with a propelling nozzle I2I.

Finally, the exhaust I04 of the low pressure compressor IN is alsoconnected with manifold chamber II2 through a conduit I22, a valve I23serving to close I22 and open I01, or vice-versa.

On the inside of manifold chamber II2 are provided partitions I24leaving passages between them whereby the two compartments formed insidechamber I I2 by these partitions and respectively interposed betweenconduits II3, Ia and H0, I22 communicate together. Each of thesecompartments is provided with injectors I25 for injecting fuel into theair present in chamber I I2, which is thus heated by the combustion ofthis fuel.

The plant illustrated by Fig. 6 works in the following manner:

When the aircraft on which this plant is fitted is flying at highaltitude, valves I09, 1, H9

- and I2! are in the positions shown in solid lines 12 from thesurrounding atmosphere by low pressure compressor Ill and delivered witha certainpressure to the high pressure compressor I 02 in which it isfurther compressed, before being sent into manifold chamber I I2. Inthis chamber the air is heated by the combustion of the fuelinjectedthrough the injectors I25 mounted in the left hand compartment of saidchamber. This hot air under pressure first expands in the high pressureturbine III, thus driving it, and then in the low pressure turbine IIO,from which it passes to nozzle I2 I, escaping therefrom into theatmosphere so as to exert the desired propelling action.

The compressor and motor devices are constructed in such manner that theefllciency of the turbines is maximum, for this working in series, athigh altitudes, which are the normal flying altitudes.

For the take off and for'flying at low altitude,

the plant must be capable of developing a very" high power. For thispurpose, the two units formed, on the one hand by the low pressurecompressor IOI and the low pressure turbine I I0 and,

on the other hand, by the high pressure compressor I02 and the highpressure turbine I II, are caused to work in parallel.

In order to obtain this result, valves I00, H1, H0, I23 are brought intothe respective positions thereof shown in dotted lines. compressor IOIthen delivers the air it has compressed, through conduit I22, directlyinto manifold chamber I I2, where this air is heated by the fuelinjected, in particular, by the injectors provided in the right handcompartment of said chamber H2. The air thus heated is introducedthrough II8 into the low pressure turbine III and after driving thisturbine escapes through propelling nozzle I2I. 7

Parallel with low pressure compressor IN, the high pressure compressorsucks in air from the atmosphere through air intake I00 and sendscompressed air into manifold chamber II2. As both compressors, to witthe high pressure one and the low pressure one, have the same ratio ofcompression, the delivery pressures of these compressors aresubstantially the same. The air fed by compressor I02 is also heated inchamber II! by the combustion of fuel injected into the left handcompartment of said chamber, and this air is subsequently fed to thehigh pressure turbine III, was to drive it and finally to escape throughpropelling nozzle H5.

As the two compartments of manifold chamber I I2 communicate together,an excess of air under pressure supplied by one of said compressorswhich cannot be absorbed by the corresponding turbine is absorbed by theother turbine which is underfed by its compressor.

Therefore, during the working in parallel, a

good efficiency of the plant is maintained owing to theintercommunication between the circuits of the two units that constitutethis plant.

In the embodiment shown by Fig. 7, the high pressure compressor I02 ofthe system of Fig. 6 is replaced by a group of auto-generators,including for instance two auto-generators I02a (-see Fig. 7b) each ofsaid generators including a compressor portion (piston C and cylinder 0)and a power portion (piston P and cylinder p) which drives saidcompressor portion and delivers hot gases under pressure.

The admission to the compressor portions of said generators isdesignated by reference character I05a, while the exhaust of the powerportions is designated by I 06a.

The low pressure As the compressor elements of the auto-generators aredriven by the motor elements ofthese machines, it is no longer necessaryfor the high pressure turbine III .to drive the high pressure compressorgroup. Therefore, in this embodiment, this turbine is utilized fordriving a blower I26 which, for the working in series, supercharges thelow pressure compressor IOI (which in the drawing is shown as having twostages) and feeds one or several propelling nozzles. whereas, for theworking in parallel, this blower supercharges both the group ofauto-generators I02a and the low pressure compressor IIII I For thispurpose, the delivery of blower I26 is connected, on the one hand and ina permanent manner, with the inlet I03 of compressor IIII, throughconduit I21, and, on the other hand, through conduit I26 and accordingto the position of valve I29, either with the admission I05a ofauto-generators I02a or with propelling nozzles I26a Turbine III isconnected with blower I26 through a Cardan shaft I30, a free wheell3land a variable ratio speed reducing gear I32. This speed reducing gearis fitted, in the known manher, with synchronizing means and permits ofpassing from one gear ratio to another without uncoupling.

The low and high pressure turbines III! and III, and also the lowpressure compressor I III, are mounted on a common support I33. Manifoldchamber II 2, which serves, during the working in parallel, to thecommon feed of both turbines III) and III, is provided with fuelinjectors I25 preferably mounted opposite'the point where the gasesproduced by the group of auto-generators enter said manifold chamber.These gases, which are already at a relatively high temperature, andwhich contain a considerable proportion of oxygen, ensure thespontaneous combustion of the fuel that is injected. As a consequence ofthis combustion, they are brought to a high temperature and, in theworking in parallel, they are mixed in manifold chamber I I2 with theair compressed by the low pressure compressor, this air being introducedinto this collecting chamber through conduits I01 and I22.

The propelling nozzles H5 and I2I may be arranged in such manner thatthe planes in which they are flattened are normal to each other, saidplanes being, for instance, vertical for nozzle I2I and horizontal fornozzle II5 (Fig. 7a)

The operation of the device shown by Fig. '7 is as follows:

For flying at high altitude, valves II I, Hi, I23 and I29 are in theposition shown in solid lines by the drawing.

The air compressed by blower I26 is partly ab-- sorbed by the lowpressure compressor IOI, while the remainder of this air feds, throughconduit I28, propelling nozzles not shown by the drawing and whichpreferably open into the atmosphere close to the trailing edges of theaircraft wings.

The air compressed by compressor IOI is introduced into theauto-generators where it first undergoes a further compression forsubsequently scavenging and feeding the motor cylinders of theseauto-generators, which feed hot gases under pressure, through conduitIlla to manifold chamber II2. As these gases have already been heated bythe fuel burned in the auto-generators, itis not absolutely necessary toinject into said gases a supplementary amount of fuel as they passthrough chamber II2. -However. in some cases, it is advantageous to doso. From manifold chamber II2, the gases are fed to turbine III, wherethey undergo a. first expansion. Then. they pass to turbine IIII wherethey undergo a second expansion. after which they finally escape throughpropelling nozzle I2I.

, For operation in parallel, valves III, I22 and I29 are brought intothe position shown in dotted lines.

In this position, blower I26 supercharges both the low pressurecompressor IIII and the compressor elements of generators I62a (sincevalve I 28 is in the position I29a shown in dotted lines for whichconduit I28 opens into admission I 05a). The air discharged by the lowpressure compressor and also the gases supplied by the auto-generatorsare introduced into manifold chamber I I2 with substantially the samepressure. The mixture thus obtained in said manifold chamber is heatedby injection of fuel through injectors I25. Then the ga es pass from themanifold chamber on the one hand into the high pressure turbine III,from which, after having driven said turbine, they escape throughconduit II4 into nozzles I I5, and, on the other hand, into turbineIII), from which they escape into nozzle I2I. Manifold chamber III,which ensures the desired intercommunicatlon between the two parallelcircuits for the gases, compensates for the differences that may existbetween the outputs of the compressors and the requirements of theturbines of the two parallel. branch circuits respectively, as'aboveexplained with reference to Fig. 6.

The plant shown by Figs. 8 and 9 differs from those of Figs. 6 and 7 inthat it permits of working not only in parallel and in series but alsowith an interconnection between the various elements of the system thatcorresponds to what will be hereinafter called compound working. Thiscompound working will be preferably used for flying at intermediatealtitude, while the working in parallel is employed for flying at lowaltitude and the working in series for flying at high altitude.

During this compound working, the low pressure turbine I I0 is fed witha mixture constituted, on the one hand, by at least a part of the gaseswhich have already been expanded to a certain degree in the highpressure turbine and, on the other hand, by at least a part of the airfed by the low pressure compressor group IIII, a certain amount of fuelbeing preferably burned in this air or in said mixture, either during orafter after the formation of the latter.

The plant shown by Figs. 8 and-9 is provided, same as that of Fig. 7,with a group of auto-generators which constitute the high pressurecompressor group. and with a blower I26, driven by the high pressureturbine I I I. This blower serves on the one hand to feed a propellingnozzle I26 and, on the other hand, to supercharge eithe the low pressurecompressor group II alone, for the compound working or the working inseries of the plant, or both the high pressure and low pressurecompressor groups for the working 'in parallel.

For this purpose, the delivery of blower I26 is connected to propellingnozzle I34 through a conduit I28a from which branches oif an air intakeI08a provided with a valve IIlQa and which serves to the superchargingof auto-generators I 02a during the working in parallel. Further- Imore, the delivery of blower I26 is' connected through conduit I26b withthe inlet I03 of the low pressure compressor group which includes.

aocaooi in the plant shown by Fig. 8, twov stages of compression. Onconduit I01 which connects the delivery of the low pressure compressorgroup with the inlet Ilia of auto-generators I02. there is mounted aconduit Ina directly connecting conduit I01 with manifold chamber IIIwhich acts as combustion chamber.

Concerning the exhaust manifold I08 of gen erators Ina, it is connected,on the one hand, through conduit II3c, directly to the inlet of the highpressure turbine III and, on the other hand, through conduit II3a, withcombustion chamber Hi. the latter being connected with the inlet of thehigh pressure turbine III through conduit II3b and with the inlet of thelow pressure turbine IIO through conduit H8. The exhaust of the highpressure turbine is connected, on the one hand, through conduit I35,with combustion chamber H2, and on the other hand,

through conduit I II, with a propelling nozzle I IS.

The fuel injectors I are mounted in combustion chamber II2 preferablyopposite the outlets of conduits I and So. This arrangement has for itseffect considerably to accelerate the combustion of the fuel since thegases coming from these conduits and which contain a considerable excessof oxygen are at a high temperature, which may be about 600 C. when thegases come directly from the auto-generators, or about 450 C. when thesegases have already expandedv in high pressure turbine I I I.

Finally, the plant includes a closing slidevalve I36 which permits ofclosing conduit I22a, and two-way cocks or valves I31, I38 and I39, andalso a throttle I40 provided in conduit m downstream of branch conduitI22a.

This system works in the following manner:

During the working in parallel indicated by the Both the auto-generatorsI02a and the low pressure compressor group IUI are fed with compressedair by blower I26, and they deliver air and gases, respectively,substantially at the same pressure, into combustion chamber I I2, wherethe mixture thus constituted is heated by the combustion of fuelinjected through injectors I25. A portion of this mixture is thenintroduced into turbine III, from which it escapes toward nozzle II5.while the other portion of the mixture is introduced into turbine IIO,from which it escapes toward propelling nozzle I2I. This working inparallel, which is utilized for the take oiI and for flying at lowaltitude therefore corresponds to the feature of the invention accordingto which there is an intercommunication between the two parallelcircuits of gases, this intercommunication being ensured by theprovision of a common combustion chamber H2.

For the so-called compound" working, which is indicated by the arrows indot-and-dash lines, Fig. 9, and is to be used chiefly for flying atintermediate altitude, but which may also be used for flying at highaltitude, air intake 108a is i6 Ina is opened by means of valve I36, andvalves I31, I3! and I3! are given the positions shown in Figs. 8 and 9by solid lines.

For this compound working, blower I28 supercharges only the low pressurecompressor group IOI which, on the other hand, feeds compressed air bothto the inlet of auto-generators I02a and to combustion chamber I I2. Thegases produced by auto-generators 12a expand a first time in highpressure turbine III and are subsequently also introduced intocombustion chamber Ill, where they mix with the air coming directly fromthe compressor group IOI. The mixture thus formed in chamber I I2, afterhaving been heated by the combustion of the fuel injected throughinjectors I25, flows toward low pressure turbine IIII. From thisturbine, the mixture is fed to propelling nozzle I.

By suitably adjusting throttle I40, it is possible to obtain the desiredpressure and flow rate of air fed to generators IMa, which isparticularly advantageous for flying at various intermediate altitudes.

For the working in series, which is indicated by the arrows in dottedlines (Fig. 9) and which is to be used especially for flying at highaltitude, conduit I22 is closed by means of valve I36. Air intake I08ais also closed by means of valve "Na, and valves I31, I38 and I39 aregiven the position shown in solid lines by Figs. 8 and 9.

The whole of the air fed by the low pressure compressor group istherefore fed to the autogenerators Him and the gases produced by thesegenerators are conveyed first to turbine I I I where they expand a firsttime, and then, through combustion chamber II2, where they may beheated, into low pressure turbine I II), where they expand azsecondtime. Then they escape through nozzle It should be noted that, in somecases, the compound working can be used also at high altitude instead ofthe series working, and this especially in case of breakdown of one orseveral generators I02a. Furthermore, in order to obtain a plant oflighter weight, this plant can be devised in such manner as to permitonly the parallel working and the compound working, the first one forflying at low altitudes, and the other for flying at high altitudes. Ofcourse, the efficiency of such a plant is lower.

Whatever be the particular embodiment that is chosen, I obtain a jetpropulsion plant having a high adaptability and efficiency.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and efllcient embodiments of the presentinvention, it should be well understood that I do not wish to be limitedthereto as there might be changes made in the arrangement, dispositionand form of the parts without departing from the principle of thepresent invention as comprehended within the scope of the appendedclaims.

What Icla-im is:

1. A jet propulsion plant which comprises, in combination, at least twodistinct compressor means, at least two distinct gas operated motormeans, means for coupling at least one of said motor means with one ofsaid compressor means for drive transmission from one to the other, gascommunication means between said motor and compressor means, means'forming at least one combustion chamber connected with saidcommunication means, jet propulsion means connected to the exhausts ofeach of said motor closed by means of valve I09a, branch conduit 7|means, and valve means for controlling said communication means adaptedto form either a single gas circuit, including at least said two motormeans in series, or two gas circuits in parallel, including each atleast one compressor means, one combustion chamber and one motor means,said plant including means forming a manifold chamber inserted in bothof said circuits in' parallel upstream of said motor means,respectively.

2. A jet propulsion plant which comprises, in combination, at least twodistinct compressor means, at least two distinct gas operated motormeans, means for coupling at least one of said motor means with one ofsaid compressor means i for drive transmission from one to the other,gas communication means between said motor and compressor means, meansforming at least one combustion chamber connected with said gascommunication means, jet propulsion means connected with the exhausts ofeach of said motor means, and valve means for controlling saidcommunication means adapted to form either a single gas circuit,including at least said two motor means in series, or two gas circuitsin parallel, including each one compressor means, said combustionchamber and one motor means, whereby said combustion chamber is commonto both circuits.

3. A jet propulsion plant which comprises, in combination, at least onelow pressure compressor means and one high pressure compressor means, atleast one low pressure motor means and one high pressure motor means,both of the gas operated type, means for coupling at least one of saidmotor means with one of said compressor means for drive transmissionfrom one to the other, conduit means for connecting the delivery 'ofsaid high pressure compressor means with the inlet of said high pressuremotor means, an internal combustion engine of the piston type having itscombustion chamber inserted in said conduit means, a propelling nozzle,means for connecting the exhaust of said low pressure motor means withsaid nozzle, an air intake for said low pressure compressor means,conduit means extending from the delivery of said low pressurecompressor means to the inlet of said high pressure compressor means,means forming a combustion chamber in communication with the inlet ofsaid low pressure motor means, means for feeding fuel to said lastmentioned combustion chamber, two-way valve means between said lastmentioned conduit means and said last mentioned combustion chamber fordirecting the flow of compressed air from said low pressure compressormeans either toward said last mentioned-combustion chamber or towardsaid high pressure compressor means, two-way valve means for connectingthe inlet of said high pressure compressor means either with said lastmentioned air intake -or with said last mentioned conduit means, apropelling nozzle, and two-way valve means for connecting the exhaust 01said high pressure motor means either with said last mentioned nozzle orwith the inlet of said low pressure motor means.

4. A jet propulsion plant which comprises, in combination, at least twodistinct compressor means, at least two distinct gas operated motormeans, means for coupling at least one of said motor means with one ofsaid compressor means for drive transmission from one to the other, gascommunication means between said motor and compressor means, meansforming at least two combustion chambers connected with saidcommunication means, jet propulsion means connected to the exhausts ofeach of said motor means, valve means for controlling said communicationmeans adapted to form either a single gas circuit, including at leastsaid two motor means in series, or two gas circuits in parallel,including each one compressor means, one combustion chamber and onemotor means, respectively, the means forming at least one of saidcombustion chambers being constituted by an internal combustion engineof the piston type, a blower coupled with said engine adapted to be fedwith air from the atmosphere, a propulsion nozzle, and means forconnecting the delivery of said blower with said nozzle.

5. A jet propulsion plant which comprises, in combination, at least twodistinct compressor means, at least two distinct gas operated motormeans, means for coupling at least one of said motor means with one ofsaid compressor means for drive transmission from one to the other gascommunication means between said motor and compressor means, meansforming at least two combustion chambers connected with saidcommunication means, jet propulsion means connected to the exhausts of'each of said motor means, valve means for controlling saidcommunication means adapted to form either a single gas circuit,including at least said two motor means in series, or two gas circuitsin parallel, including each one compressor means,

one combustion chamber and one motor means, respectively, the meansformin at least one of said combustion chambers being constituted by aninternal combustion engine of the piston type, a blower coupled withsaid engine adapted to be fed with air from the atmosphere, and meansfor connecting the delivery of said blower with the inlet of at leastone of said compressor means.

6. A jet propulsion plant which comprises, in combination, at least twodistinct compressor means, at least two distinct gas operated motormeans, means for coupling at least one of said motor means with one ofsaid compressor means for drive transmission from one to the other, gascommunication means between said motor and compressor means, meansforming at least two combustion chambers connected with saidcommunication means, jet propulsion means connected to the exhausts ofeach of said motor means, valve means for controlling said communicationmeans adapted to form either a single gas circuit, including at leastsaid two motor means in series, or two gas circuits in parallel,including each one compressor means, one combustion chamber and onemotor means, respectively, the means forming at least one of saidcombustion chambers being constituted by an internal combustion engineof the piston type, a blower coupled with said engine adapted to be fedwith air from the atmosphere, a propulsion nozzle, means for connectingthe delivery of said blower with said nozzle, and means for connectingthe delivery of said blower with the inlet of at least one of saidcompressor means.

7. A jet propulsion plant which comprises, in combination, at least onelow pressure compressor means, at least one auto-generator in-- cludinga motor element and a compressor element, at least one low pressuremotor means and one high pressure motor means, both of the gas operatedtype, means for coupling said low pressure motor means with said lowpressure compressor means for drive transmission from one to the other,conduit means for connecting the delivery of said auto-generatorcompressor element with the inlet of said high pressure motor means, thecombustion chamber of the motor element of said auto-generator beinginserted in said conduit means, a propelling nozzle, means forconnecting the exhaust of said low pressure motor means with saidnozzle, an air intake for said low pressure compressor means, conduitmeans extending from the delivery of said low pressure compressor meansto the inlet of said auto-generator compressor element, means forming acombustion chamber in communication with the inlet of said low pressuremotor means, means for feeding fuel to said last mentioned combustionchamber, two-way valve means between said last mentioned conduit meansand said last mentioned combustion chamber for directing the flow ofcompressed air from said low pressure compressor means either towardsaid last mentioned combustion chamber or toward said auto-generatorcompressor element, two-way valve means for connecting the inlet of saidauto-generator compressor element either with said last mentioned airintake or with said last mentioned conduitv means, a propelling nozzle,and two-way valve means for connecting the exhaust of said high pressuremotor means either with said last mentioned nozzle or with the inlet ofsaid low pressure motor means.

8. A jet propulsion plant which comprises, in combination, at least onelow pressure compressor means, at least one auto-generator including amotor element and a compressor element, at least one low pressure motormeans and one high pressure motor means, both of the gas operated type,means for coupling said low pressure motor means with said low pressurecompressor means for drive transmission from one to the other, conduitmeans for connecting the delivery or said auto-generator compressorelement with the inlet of said high pressure motor means, the combustionchamber of the motor element of said auto-generator being inserted insaid conduit means, a propelling nozzle, means for connecting theexhaust of said low pressure motor means with said nozzle, an air intakefor said low pressure compressor means, conduit means extending from thedelivery of said low pressure compressor means to the inlet of saidauto-generator compressor element, means forming a combustion chamber incom munication with the inlet of said low pressure motor means, meansfor feeding fuel to said last mentioned combustion chamber, two-wayvalve means between said last mentioned conduit means and said lastmentioned combustion chamber for directing the flow of compressed airfrom said low pressure compressor means either toward said lastmentioned combustion chamber or toward said auto-generator compressorelement, two-way valve means for connecting the inlet of saidauto-generator compressor element either with said last mentioned airintake or with said last mentioned conduit means. a propelling nozzle,two-way valve means for connecting the exhaust of said high pressuremotor means either with said last mentioned nozzle or with the inlet ofsaid low pressure motor means, a blower coupled with said high pressuremotor means so as to be driven by it, adapted to be fed with air fromthe atmosphere, a propulsion nozzle, and means for connecting thedelivery of said blower with said nozzle.

9. A jet propulsion plant which comprises, in combination, at least onelow pressure compressor means, at least one auto-generator including amotor element and a compressor element, at

least one low pressure motor means and one pressure motor means, bothoi. the gas operated type, means for coupling said low pressure motormeans with said low pressure compressor means for drive transmissionfrom one to the other. conduit means for connecting the delivery or saidauto-generator compressor element with the inlet of said high pressuremotor means, the combustion chamber oi the motor element of saidauto-generator being inserted in said conduit means, a propellingnozzle, means for connecting the exhaust of said low pressure motormeans with said nozzle, an air intake for said low pressure compressormeans, conduit means extending from the delivery of said low pressurecompressor means to the inlet oi. said auto-generator compressorelement, means forming a combustion chamber in communication with theinlet or said low pressure motor means, means for feeding fuel to saidlast mentioned combustion chamber, two-way valve means between said lastmentioned conduit means and said last mentioned combustion chamber fordirecting the flow or compressed air from said low pressure compressormeans either toward said last mentioned combustion chamber or towardsaid auto-generator compressor element, two-way valve means forconnecting the inlet of said auto-generator compressor element eitherwith said last mentioned air intake or with said last mentioned conduitmeans, apropelling nozzle, two-way valve means for connecting theexhaust of said high pressure motor means either with said lastmentioned nozzle or with the inlet of said low pressure motor means, ablower coupled with said high pressure motor means so as to be driven byit, adapted to be fed with air from the atmosphere, and means forconnecting the delivery of said blower with the inlet of at least one ofsaid compressor means.

10. A jet propulsion plant which comprises, in combination, at least onelow pressure compressor means, at least one auto-generator including amotor element and a compressor element, at least one low pressure motormeans and one high pressure motor means, both of the gas operated type,means for coupling said low pressure motor means with said low pressurecompressor means for drive transmission from one to the other, conduitmeans for connecting the delivery of said auto-generator compressorelement with the inlet of said high pressure motor means, the combustionchamber of the motor element of said auto-generator being inserted insaid conduit means, a propelling nozzle, means for connecting theexhaust of said low pressure motor means with said nozzle, an air intakefor said low pressure compressor means, conduit means extending from thedelivery of said low pressure compressor means to the inlet of saidauto-generator compressor element, means forming a combustion chamber incommunication with the inlet of said low pressure motor means, means forfeeding fuel to said last mentioned combustion chamber, twoway valvemeans between said last mentioned conduit means and said last mentionedcombustion chamber for directing the flow of compressed air from saidlow pressure compressor means either toward said last mentionedcombustion chamber or toward said auto-generatgr compressor element,two-way valve means for connecting the inlet of said auto-generatorcompressor element either with said last mentioned air intake or withsaid last mentioned conduit means, a propelling nozzle, two-way valvemeans for conhigh 7 necting the exhaust 01 said high pressuremotor meanseither with said last mentioned nozzle or with the inlet of said lowpressure motor means, a blower coupled with said high pressure motormeans so as to be driven by it, adapted to be fed with air from theatmosphere, a propulsion nozzle, means for connecting the delivery ofsaid blower with said nozzle, and means for connecting the delivery ofsaid blower with the inlet of at least one of said compressor means.

11. A jet propulsion plant which comprises, in combination, at least onelow pressure compressor means, at least one auto-generator includin amotor element and a compressor element, at least one low pressure motormeans and one high pressure motor means, both of the gas operated type,means for coupling said low pressure motor means with said low pressurecompressor means for drive transmission from one to the other. conduitmeans for connecting the delivery of said auto-generator compressorelement with the inlet of said high pressure motor means, the combustionchamber of the motor element of said autogenerator being inserted insaid conduit means, a propelling nozzle, means for connecting theexhaust of said low pressure motor means with said nozzle, an air intakefor said low pressure compressor means, conduit means extending from thedelivery of said low pressure compressor means to the inlet of saidauto-generator com pressor element, means forming a combustion chamberin communication with the inlet of said low pressure motor means, meansfor feeding fuel to said last mentioned combustion chamber, twoway valvemeans between said last mentioned conduit means and said last mentionedcombustion chamber for directing the flow of compressed air from saidlow pressure compressor means either toward said last mentionedcombustion chamber or toward said autogenerator compressor element,two-way valve means for connecting the inlet of said auto-generatorcompressor element either with said last mentioned air intake or withsaid last mentioned conduit means, a propelling nozzle, two-way valvemeans for connecting the exhaust of said high pressure motor meanseither with said last mentioned nozzle or with the inlet of said lowpressure motor means, a blower, means for coupling said blower with saidhigh pressure motor means including a Cardan shaft, a free wheel, and avariable ratio speed reducing gear including synchronizing means adaptedto permit gear changing without uncoupling, a propulsion nozzle, andmeans for connecting the delivery of said blower with said nozzle.

12. A jet propulsion plant which comprises, in combination, at least onelow pressure compressor means, at least one auto-generator including amotor element and a compressor element, at least one low pressure motormeans and one high pressure motor means, both of the gas operated type,means ,for coupling said low pressure motor means with said low pressurecompressor means for drive transmission from one to the other, conduitmeans for connecting the delivery of said auto-generator compressorelement with the inlet of said high pressure motor means, the combustionchamber of the motor element of said auto-generator being inserted insaid conduit means, a propelling nozzle, means for connecting theexhaust of said low pressure motor means with said nozzle, an air intakefor said low pressure compressor means, conduit means extending from thedelivery or said low pressure compressor means to the inlet of saidauto-generator compressor element, means forming a combustion chamber incommunication with the inlet of said low pressure motor means, means forfeeding fuel to said last mentioned combustion chamber, two-way valvemeans between said last mentioned conduit means and said last mentionedcombustion chamber for directing the flow of compressed air from saidlow pressure compressor means either toward said last mentionedcombustion chamber or toward said auto-generator compressor element,two-way valve means for connecting the inlet of said auto-generatorcompressor element either with said last mentioned air intake or withsaid last mentioned conduit means, a propelling nozzle, two-way valvemeans for connecting the 'exhaust or said high pressure motor meanseither with said last mentioned nozzle or with the inlet of said lowpressure motor means, a blower, means for coupling said blower with saidhigh pressure motor means including a Cardan shaft, a free wheel, and avariable ratio speed reducing gear including synchronizing means adaptedto permit gear changing without uncoupling, and means for connecting thedelivery of said blower with the inlet of at least one of saidcompressor means.

13. A jet propulsion plant which comprises, in combination, at least onelow pressure compressor means, at least one auto-generator including amotor element and a'compressor element. at least one low pressure motormeans and one high pressure motor means, both of the gas operated type,means for coupling said low pressure motor means with said low pressurecompressor means for drive transmission from one to the other, conduitmeans for connecting the delivery of said auto-generator compressorelement with the inlet of said high pressure motor means, the combustionchamber of the motor element of said auto-generator being inserted insaid conduit means, a propelling nozzle, means for connecting theexhaust of said low pressure motor means with said nozzle, an air intakefor said low pressure compressor means, conduit means extending from thedelivery of said low pressure compressor means to the inlet of saidauto-generator compressor element, means forming a combustion chamber incommunication with the inlet of said low pressure motor means, means forfeeding fuel to said last mentioned combustion chamber, two-way valvemeans between said last mentioned conduit means and said last mentionedcombustion chamber for directing the flow of compressed air from saidlow pressure compressor means either toward said last mentionedcombustion chamber or toward said auto-generator compressor element,twoway valve means for connecting the inlet of said auto-generatorcompressor element either with said last mentioned air intake or withsaid last mentioned conduit means, a propelling nozzle, two-way valvemeans for connecting the exhaust of said high pressure motor meanseither with said last mentioned nozzle or with the inlet of said lowpressure motor means, a blower, means for coupling said blower with saidhigh pressure motor means including a Cardan shaft, a free wheel, and avariable ratio speed reducing gear including synchronizing means adaptedto permit gear changing without uncoupling, a propulsion nozzle, meansfor connecting the delivery 76 of said blower with said nozzle, andmeans for connecting the delivery of said blower with the inlet of atleast one of said compressor means.

14. A jet propulsion plant for an aircraft which comprises, incombination, at least two distinct compressor means, at least twodistinct gas operated motor means, means for coupling at least one ofsaid motor means with one of said compressor means for drivetransmission from one to the other, gas communication means between saidmotor and compressor means, means forming at least one combustionchamber connected with said communication mea .s, jet propulsion meansconnected to the exhausts of each of said motor means, valve means forcontrolling said communication means adapted to form either a single gascircuit, including at least said two motor means in series, or two gascircuits in parallel, including each at least one compressor means, onecombustion chamber and one motor means, and barometric means foroperating said valve means in response to variations of altitude of theaircraft.

15. A jet propulsion plant which comprises, in combination, at least twodistinct compressor means, at least two distinct gas operated motormeans, means for coupling at least one of said motor means with one ofsaid compressor means for drive transmission from one to the other,

I gas communication means between said motor and compressor means, meansforming at least one main combustion chamber connected with saidcommunication means, means for feeding fuel to said combustion chamber,jet propulsion means connected to the exhausts of each of said motormeans, valve means for controlling said communication means adapted toform either a single gas circuit, including at least said two motormeans in series, or two gas circuits in parallel, including each atleast one compressor means, one combustion chamber and one motor means,an auxiliary combustion chamber, means for feeding fuel to saidauxiliary combustion chamber, means for sending a portion of the gas onits way toward said main combustion chamher into said auxiliarycombustion chamber, and

means for returning said gas portion from said auxiliary combustionchamber toward said main combustion chamber to mix with the remainder ofthe gas stream on its way to said main chamber, whereby, after mixing,the whole gas stream is at a temperature such that fuel ignitesspontaneously therein in said main combustion chamber.

16. A jet propulsion plant which comprises, in combination, at least twodistinct compressor means, at least two distinct gas operated motormeans, means for coupling at least one of said motor means with one ofsaid compressor means for drive transmission from one to the other, gascommunication means between said motor and compressor means, meansforming at least one combustion chamber connected with saidcommunication means, jet propulsion means connected to the exhausts ofeach of said motor means, valve means for controlling said communicationmeans adapted to form either a single gas circuit, including at leastsaid two motor means in series, or two gas circuits in parallel,including each at least one compressor means, one combustion chamber andone motor means, means for injecting fuel into said combustion chamber,means for limiting the amount of fuel fed by said injecting means, andmeans responsive to temperature variations in said combustion chamberfor adjusting said limiting means.

ROBERT JEAN POUIT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 608,969 Parsons Aug. 9, 18982,115,112 Lysholm Apr. 26, 1938 2,396,911 Anxionnaz et al. Mar. 19, 19462,411,227 Planiol et al Nov. 19, 1946 2,466,282 Sparrow Apr. 5, 1949FOREIGN PATENTS Number Country Date 210,653 Switzerland Oct. 16, 1940

